In recent years, a mobile communication unit such as a cell phone unit, a PHS (personal handy-phone system) and the like has been considerably reduced in size and in weight. However, such a mobile communication unit has its essential construction remain substantially unchanged. In other words, the mobile communication unit is essentially constructed of its components contained in a single-piece casing, which components are, for example such as: a wireless telephone functional portion; a battery portion; a display portion; a control portion; a microphone portion; and, an ordinary air-conduction speaker portion. Consequently, in use, it is necessary for the user of such mobile communication unit to have his/her ear and mouth disposed adjacent to the air-conduction speaker portion and the microphone portion of the mobile communication unit, respectively. Due to this, it is difficult to further downsize the today's mobile communication unit having the above essential construction.
Although there are various types of external components such as external ear phones and external microphones which are connected with the mobile communication system when used in place of the system's built-in speaker and microphone, any one of these external components is connected with the mobile communication system through an electric connecting cord. Due to the presence of this connecting cord, handling of such external components is relatively cumbersome, which impairs the mobile communication system in portability and in wearability (i.e., suitability for being worn or fit). This makes it difficult for the user of this type of mobile communication unit to immediately answer a telephone call.
In this connection, an ultra-compact mobile communication unit of a wrist-mounted type has been experimentally developed. However, in use, when the user has a speaker portion of this type of ultra-compact unit brought into contact with his/her ear to answer a phone call, it is impossible for the user to have a microphone portion of this ultra-compact unit disposed adjacent to his/her mouth, which makes it difficult for the microphone portion of the unit to catch the user's voice sound. Further, in the case where an external earphone is used in place of the speaker portion of this wrist-mounted type ultra-compact mobile communication unit, an electric connecting cord extending from the user's wrist to his/her ear is a must for such wrist-mounted type unit. However, the presence of this connecting cord impairs such wrist-mounted type unit in wearability (i.e., suitability for being worn).
As described above, the wrist-mounted type ultra-compact mobile communication unit, which is much smaller in size than a conventional cell phone and the like, suffers from various types of disadvantages. Consequently, it is an object of the present invention to provide an ultra-compact mobile communication unit which is smaller in size and lighter in weight. Furthermore, this ultra-compact mobile communication unit enables a user thereof to easily perceive any sounds in communication even in a high-noise environment, and also enables the user to speak in a whisper without making the people around the user uncomfortable.
The ultra-compact mobile communication unit of the present invention may be any one of cell phones, personal handy-phone systems and the like, which one is characterized by its bone conduction speaker. This bone conduction speaker is separated from a main body of the mobile communication unit, and enables its user to catch any voice sound received by the mobile communication unit, without fail.
Further, the present invention is characterized in that the ultra-compact mobile communication unit is detachably mounted on an inner side of the user's wrist with the use of a band and the like.
Still further, the present invention is characterized in that the ultra-compact mobile communication unit uses a bone conduction speaker provided with a vibrating portion, wherein the vibrating portion of the bone conduction speaker has its rear surface formed into a finger-mounted portion which assumes a cap shape or a ring shape to enable the bone conduction speaker to be mounted on a finger tip of the user.
Further, the present invention is characterized in that an electric connecting cord through which the bone conduction speaker is electrically connected with a main body of the ultra-compact mobile communication unit is capable of being withdrawn into the main body of the unit by using a take-up reel and like means which is mounted in the main body of the mobile communication unit.
Still further, the present invention is characterized in that the main body of the ultra-compact mobile communication unit is provided with a clip in a rear side of the main body, wherein the clip enables the main body of the mobile communication unit to be mounted on a band of the user's wrist watch.